Hydrodynamic torque converter

ABSTRACT

The invention relates to a hydrodynamic torque converter having a pump shell including blades, a turbine shell including blades, a torus-shaped flow cycle. The blades are configured to be attached at the respective shells through inner walls and the inner walls of the turbine shell and of the pump shell form an inner torus with outer surfaces facing the flow cycle and an end of an extension of the inner wall of at least one shell and an end of an extension of an adjacent shell are disposed in a plane and extend over one another and define a gap between one another. A transition from the extensions is configured to be hydrodynamically smooth.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No. 102009 051 221.7, filed Oct. 29, 2009, which application is incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to a hydrodynamic torque converter.

BACKGROUND OF THE INVENTION

Hydrodynamic torque converters of this type are generally known. Theyinclude a torus-shaped fluid flow cycle formed by a pump shell, aturbine shell and possibly a stator shell and fluid included in thefluid cycle. Blades are disposed at each of the shells of the pump shelland the turbine shell, where the blades are attached at the respectiveshells through suitable walls and the blades are supported at theshells. The walls respectively include inner walls, where the innerwalls of the pump shell together with the inner walls of the turbineshell and possibly the inner walls of the stator shell form an innertorus, where the blades of the shells can interact with the fluid flowin the flow cycle outside of the inner torus. The shells are proximal toone another along the torus-shaped flow cycle with a slot left betweenthem. Fluid flowing in the flow cycle, however, can move into the innerportion of the inner torus through the slot.

German Patent No. 198 03 173 B4 illustrates a configuration of anextension of the inner wall of a shell configured to prevent a leakageflow from the torus-shaped flow cycle into the inner portion of theinner torus. Thus, an end of the extension of the inner wall of a shellreaches over an end of an extension of an adjacent shell with a radialgap formed between the ends. This facilitates shielding the flow cycleagainst the inner portion of the inner torus and reduces the leakageflow. However, the respective outer surfaces of the extensions facingthe flow cycle are radially offset relative to one another, whichdisturbs the fluid flowing in the torus-shaped flow cycle and reducesthe efficiency of the hydrodynamic torque converter.

Thus, it is the object of the invention to improve the efficiency of ahydrodynamic torque converter.

The object is achieved through a hydrodynamic torque converter.

BRIEF SUMMARY OF THE INVENTION

Accordingly, a hydrodynamic torque converter is proposed which comprisesa pump shell and a turbine shell, respectively, including blades and atorus-shaped flow cycle, wherein the blades are configured to beattached at the respective shells through inner walls and the innerwalls of the turbine shell and of the pump shell form an inner toruswith outer surfaces facing the flow cycle. An end of an extension of theinner wall of at least one shell and an end of an extension of anadjacent shell are disposed in a plane or reach over one another, e.g.,in a form of an overlap. The ends define a gap between one another and atransition from the extensions is configured to be hydrodynamicallysmooth. For example, a theoretical fluid element of the flow in the flowcycle in the portion of the transition and in particular over the gap isessentially straight or only slightly curved. This helps to reducevortices of the flow in the flow cycle in the transition portion whichcan cause a reduction of the flow resistance in the flow cycle and whichimproves the efficiency of the hydrodynamic torque converter.

In an embodiment according to the invention, the outer surfaces of theextensions are disposed in one plane in the transition portion.Advantageously, the extension is configured as an extension of an innerwall of the adjacent shell or it is configured as an inner wall itself.The extension can be formed at the pump shell, at the turbine shell, orcombinations thereof. In an advantageous embodiment, the transition isformed in the radially outer portion, in the radially inner portion ofthe inner torus, or combinations thereof.

In another embodiment of the invention, the flow cross-section width ofthe gap is configured to be variable. The flow resistance, e.g., thefriction resistance at the defining surface of the gap, should be aslarge as possible in order to limit the leakage flow through the gap.

In another embodiment according to the invention, the thickness of theextensions varies in the transition portion, which can yield particulargap shapes. Advantageously, a radial extension is formed at least at oneextension, which helps to increase the flow resistance in the gap.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature and mode of operation of the present invention will now bemore fully described in the following detailed description of theinvention in view of the accompanying drawing figures, in which:

FIG. 1 a illustrates a cross-section of a hydrodynamic torque converterfor an embodiment of the invention between a pump shell and a turbineshell;

FIGS. 1 b through 1 f illustrate a detail view of area A of FIG. 1 a andadditional alternative embodiments for the transition;

FIG. 2 a illustrates a cross-section through a hydrodynamic torqueconverter for another embodiment of the invention between the pump shelland the turbine shell; and,

FIGS. 2 b through 2 f illustrate a detail view of area B of FIG. 2 a andadditional alternative embodiments of the transition.

DETAILED DESCRIPTION OF THE INVENTION

At the outset, it should be appreciated that like drawing numbers ondifferent drawing views identify identical, or functionally similar,structural elements of the invention. While the present invention isdescribed with respect to what is presently considered to be thepreferred aspects, it is to be understood that the invention as claimedis not limited to the disclosed aspects.

Furthermore, it is understood that this invention is not limited to theparticular methodology, materials and modifications described and, assuch, may, of course, vary. It is also understood that the terminologyused herein is for the purpose of describing particular aspects only,and is not intended to limit the scope of the present invention, whichis limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood to one of ordinary skill inthe art to which this invention belongs. Although any methods, devicesor materials similar or equivalent to those described herein can be usedin the practice or testing of the invention, the preferred methods,devices, and materials are now described.

FIG. 1 a illustrates a cross-sectional view of hydrodynamic torqueconverter 10 for an embodiment of the invention. Hydrodynamic torqueconverter 10 includes pump shell 12, turbine shell 14 and stator shell16, which define in combination a torus-shaped, hydrodynamic flow cyclefor a fluid introduced into the converter housing. The effectivecoupling of the shells configured as pump shell 12, turbine shell 14,and stator shell 16 with the fluid is provided through bladesrespectively provided at the edges of the shells. The blades areattached to the shells through walls and are supported by the walls. Thewalls are formed by outer walls 20 and inner walls 18. Inner walls 18 ofthe shells form inner torus 22. The fluid flows essentially intooperating portion 26 defined by the circumferential portion betweenouter walls 20 and inner walls 18. Since pump shell 12 and turbine shell14 are rotatable relative to one another and can therefore rotate atdifferent speeds, they are spatially separated from one another throughslot 24. The same applies between turbine shell 14 and stator shell 16and between pump shell 12 and stator shell 16.

Slots 24 interrupt the circumferential extension of inner torus 22 alongthe torus-shaped flow path of the fluid. Thus, the fluid can leak fromoperating portion 26 defined circumferentially between outer walls 20and inner walls 18 into inner portion 28 of inner torus 22 and thuscause flow losses, which can reduce the efficiency of hydrodynamictorque converter 10. In order to reduce the flow losses, hydrodynamictorque converter 10 in this embodiment of the invention includesextension 30 of inner wall 18 at pump shell 12 and extension 32 of innerwall 18 of turbine shell 14 in the radially outer portion of inner torus22. Ends 36, 38 of extensions 30, 32 overlap in a direction along thetorus-shaped flow path and include gap 34 between one another.

FIGS. 1 b through 1 f illustrate a detail view of area A of FIG. 1 a andillustrate additional alternative embodiments of transition 40 betweenextension 30 of inner wall 18 of pump shell 12 and extension 32 of innerwall 18 of turbine shell 14. In FIG. 1 b, transition 40 betweenextension 30 of inner wall 18 of pump shell 12 and extension 32 of innerwall 18 of adjacent turbine shell 14 is configured to behydrodynamically smooth. That is, surfaces 44 and 46 are in alignment.Outer surfaces 44, 46 of extensions 30, 32, facing flow path 42 of fluidthrough the pump, turbine, and stator are thus configured to be smoothin the portion of transition 40, so that flow path 42 is not impeded byany obstruction. Ends 36, 38 of extensions 30, 32 are beveled in acomplementary manner, so that the largest defining surface possible isprovided for the fluid entering inner portion 28 through gap 34 andthus, as a consequence, the greatest possible friction resistance. Thus,the flow loss through gap 34 towards inner portion 28 of inner torus 22can be further reduced.

In FIG. 1 c, extension 32 of turbine shell 14 includes radial extension48. End 38 of extension 32 of turbine shell 14 reaches over end 36 ofextension 30 of adjacent pump shell 12. The friction resistance for thefluid flowing through gap 34 is increased by radial extension 48 incombination with adjacent end 36 of extension 30 of the pump shell 12.Outer surfaces 44, 46 of extensions 30, 32 are configured to behydrodynamically smooth.

FIGS. 1 d through 1 f illustrate additional possible alternatives inwhich transition 40 with outer surfaces 44, 46 is hydrodynamicallysmooth and the friction resistance of the flow through gap 34 towardsinner portion 28 of inner torus 22 is increased, for example, byconfiguring the defining surface of the gap 34 as large as possible andthe gap dimensions as small as possible. In FIG. 1 e, ends 36, 38 ofextensions 30, 32 are disposed in plane 50, which means ends 36, 38 donot overlap one another, but are adjacent to one another with respect toplane 50.

FIG. 2 a illustrates a cross-sectional view of hydrodynamic torqueconverter 10 according to another embodiment of the invention. FIGS. 2 bthrough 2 f illustrate example embodiments. Pump shell 12 and turbineshell 14 respectively include extensions 30, 32 of inner walls 18 in theradially inner portion of inner torus 22. The extensions are adjacent toone another radially above stator shell 16 and include transition 40.The embodiments shown in FIGS. 2 b through 2 f are comparable with FIGS.1 b through 1 f with the difference that the overlap of walls 18 occursat the interface of portion 28 with the stator. Thus, the embodimentshown in FIG. 2 e illustrates gap 34 with constant flow cross-sectionwidth 52, whereas flow cross-section width 52 for the respectiveembodiments shown in FIGS. 2 b, 2 d, and 2 f varies. In addition,thickness 54 of extensions 30, 32 in portion of transition 40 varieswith the distance to extension 32 or 30, respectively, as can be seen inFIG. 2 c.

The extension can also be attached at the pump shell and the extensionof the inner wall can be attached at the turbine shell. Furthermore, afirst shell can include an extension, whereas the second, adjacent shelldoes not necessarily include an inner wall extension. In this case, theextension of the first shell is adjacent to the inner wall of theadjacent, second shell.

It should be understood that the invention is not limited to theembodiments shown and that combinations of the embodiments shown orcombinations of various aspects of the embodiments shown are possible.

Thus, it is seen that the objects of the present invention areefficiently obtained, although modifications and changes to theinvention should be readily apparent to those having ordinary skill inthe art, which modifications are intended to be within the spirit andscope of the invention as claimed. It also is understood that theforegoing description is illustrative of the present invention andshould not be considered as limiting. Therefore, other embodiments ofthe present invention are possible without departing from the spirit andscope of the present invention.

LIST OF REFERENCE NUMBERS

-   10 hydrodynamic torque converter-   12 pump shell-   14 turbine shell-   16 stator shell-   18 inner wall-   20 outer wall-   22 inner torus-   24 slot-   26 operating portion-   28 inner portion-   30 extension-   32 extension-   34 gap-   36 end-   38 end-   40 transition-   42 flow path-   44 outer surface-   46 outer surface-   48 radial extension-   50 plane-   52 flow cross-section width-   54 thickness

1. A hydrodynamic torque converter, comprising: a pump shell, includinga first plurality of blades attached to a first inner wall for the pumpshell; a turbine shell, including a second plurality of blades attachedto a second inner wall for the turbine shell; and, an inner toruspartially formed by the first and second inner walls, wherein the firstand second inner walls include first and second surfaces, respectively,facing away from the inner torus; the first and second inner wallsinclude first and second ends, respectively; one of the first or secondinner walls extends beyond the first or second pluralities of blades,respectively; a gap is formed between the first and second ends; thefirst and second surfaces are in alignment, at the gap; and, the firstand second ends are in alignment with a line orthogonal to an axis ofrotation for the torque converter.
 2. The hydrodynamic torque converterof claim 1, wherein the first inner wall extends beyond the firstplurality of blades.
 3. The hydrodynamic torque converter of claim 1,wherein the second inner wall extends beyond the second plurality ofblades.
 4. The hydrodynamic torque converter of claim 1, wherein thefirst inner wall extends beyond the first plurality of blades and thesecond inner wall extends beyond the second plurality of blades.
 5. Thehydrodynamic torque converter of claim 1, wherein the gap is formed at aradially outer portion of the inner torus.
 6. The hydrodynamic torqueconverter of claim 1, wherein the gap is formed at a radially innerportion of the inner torus.
 7. The hydrodynamic torque converter ofclaim 1, wherein the gap is formed at both a radially outer portion ofthe inner torus and at a radially inner portion of the inner torus. 8.The hydrodynamic torque converter of claim 1, wherein a flowcross-section width of the gap varies according to a location of theflow cross-section within the gap.
 9. The hydrodynamic torque converterof claim 1, wherein a thickness of a portion of the first inner wallvaries according to a position of the portion with respect to the gap.10. The hydrodynamic torque converter of claim 1, wherein a thickness ofa portion of the second inner wall varies according to a position of theportion with respect to the gap.
 11. The hydrodynamic torque converterof claim 1, wherein a respective radial extension is formed at the firstend.
 12. The hydrodynamic torque converter of claim 1, wherein arespective radial extension is formed at the second end.
 13. Ahydrodynamic torque converter, comprising: a pump shell, including afirst plurality of blades attached to a first inner wall for the pumpshell; a turbine shell, including a second plurality of blades attachedto a second inner wall for the turbine shell; and, an inner toruspartially formed by the first and second inner walls, wherein the firstand second inner walls include first and second surfaces, respectively,facing away from the inner torus; the first and second inner wallsinclude first and second ends, respectively; one of the first or secondinner walls extends beyond the first or second pluralities of blades,respectively; a gap is formed between the first and second ends; thefirst and second surfaces are in alignment, at the gap; and, a lineorthogonal to an axis of rotation for the torque converter overlaps thefirst and second inner walls.
 14. The hydrodynamic torque converter ofclaim 13, wherein the first inner wall extends beyond the firstplurality of blades.
 15. The hydrodynamic torque converter of claim 13,wherein the second inner wall extends beyond the second plurality ofblades.
 16. The hydrodynamic torque converter of claim 13, wherein thefirst inner wall extends beyond the first plurality of blades and thesecond inner wall extends beyond the second plurality of blades.
 17. Thehydrodynamic torque converter of claim 13, wherein the gap is formed ata radially outer portion of the inner torus.
 18. The hydrodynamic torqueconverter of claim 13, wherein the gap is formed at a radially innerportion of the inner torus.
 19. The hydrodynamic torque converter ofclaim 13, wherein the gap is formed at both a radially outer portion ofthe inner torus and at a radially inner portion of the inner torus. 20.The hydrodynamic torque converter of claim 13, wherein a flowcross-section width of the gap varies according to a location of theflow cross-section within the gap.
 21. The hydrodynamic torque converterof claim 13, wherein a thickness of a portion of the first inner wallvaries according to a position of the portion with respect to the gap.22. The hydrodynamic torque converter of claim 13, wherein a thicknessof a portion of the second inner wall varies according to a position ofthe portion with respect to the gap.
 23. The hydrodynamic torqueconverter of claim 13, wherein a respective radial extension is formedat the first end.
 24. The hydrodynamic torque converter of claim 13,wherein a respective radial extension is formed at the second end.